ज्योतिषामपि तज्ज्योतिस्तमसः परमुच्यते | ज्ञानं ज्ञेयं ज्ञानगम्यं हृदि सर्वस्य विष्ठितम् ||१३-१८||
jyotiṣāmapi tajjyotistamasaḥ paramucyate . jñānaṃ jñeyaṃ jñānagamyaṃ hṛdi sarvasya viṣṭhitam ||13-18||
Chapter 13 · Verse 18
Kshetra Kshetrajna Vibhaga Yoga
क्षेत्रक्षेत्रज्ञविभागयोग
In plain words
The Supreme Self illumines the intellect the mind the sun moon stars fire and lightning. It is selfluminous. The sun does not shine there nor do the moon and the stars nor do these lightnings shine and much less this fire.
Translation
13.18 The light of all lights, this is said to be beyond Tamas (darkness). It is known to be knowledge. It is to be attained by knowledge. It is present in the heart of all.
Meaning
The Supreme Self illumines the intellect the mind the sun moon stars fire and lightning. It is selfluminous. The sun does not shine there nor do the moon and the stars nor do these lightnings shine and much less this fire. When It shines everything shines after It all these shine by Its Light. (Kathopanishad 5.15 also Svetasvataropanishad 6.14) Knowledge Such as humility. (Cf. XIII.7to11) The knowable As described in verses 12 to 7. The goal of knowledge i.e. capable of being understood by wisdom. These three are installed in the heart (Buddhi) of every living being. Though the light of the sun shines in all objects yet the suns light shines more brilliantly in all bright and clean objects such as a mirror. Even so though Brahman is present in all objects the intellect shines with special effulgence received from Brahman. (Cf. X.20XIII.3XVIII.61)
Word by word
ज्योतिषाम् of lights अपि even तत् That ज्योतिः Light तमसः from darkness परम् beyond उच्यते is said (to be) ज्ञानम् knowledge ज्ञेयम् that which is to be known ज्ञानगम्यम् attainable by knowledge हृदि in the heart सर्वस्य of all विष्ठितम् seated.